A lack of oversight of the national repository of Medicaid data caused an estimated $36.7 billion in payment errors in 2017, according to a new Government Accountability Office report. That’s up from an estimated $14.4 billion in improper payments in Fiscal Year 2013.

Transformed Medicaid Statistical Information System (T-MSIS) is CMS’ core effort to improve Medicaid data by increasing the scope of data and quality of state-reported data.

About 49 states began reporting that data to the national repository in November, up from just 18 states the year prior. The data help federal administrators to identify potential fraud and improve the efficiency of the program, but data aren’t sufficient enough for an effective oversight of the program.

“CMS has taken an important step toward developing a reliable national repository for Medicaid data,” the GAO report authors wrote. “However, data challenges have hindered states’ and CMS’s use of the T-MSIS data for oversight.”

For example, the reported data was incomplete for all of the selected six states reporting data in August 2017 as the states said that “certain unreported elements were contingent on federal or state actions and others weren’t applicable to the state’s Medicaid program.”

Further, states failed to mention in documentation whether those elements would be reported in the future, or when they would report complete data.

Six of eight selected states actually expressed concerns about how T-MSIS data could be compared across states. While all states reported interest in information sharing across states, CMS hasn’t compiled or shared information about states’ data limitation – an act that would help states improve accuracy when comparing data between states.

Although CMS has taken those first steps to using T-MSIS data, it doesn’t yet have a plan or even a timeframe to use this data for oversight.

“As a result, important CMS goals for T-MSIS, such as reducing states’ reporting burden and enhancing program integrity activities, are not being fully realized,” the report authors wrote.

GAO officials recommend CMS improve the completeness and comparability of T-MSIS data to accelerate the program, in addition to articulating a specific oversight plan.

The U.S. Department of Health and Human Services agreed with those recommendations and said it would continue to work on obtaining complete T-MSIS data from states. Further, the agency said it will take steps to address data sharing limitations within states, along with helping states collaborate.

“Strong Medicaid data can help the federal government and the states move toward better health outcomes and improve program integrity, performance, and financial management,” HHS officials told GAO, according to the report.